Description:
The following site closure activities were performed at the CAU 428 site located at the TTR and are documented in this report: Preplanning and site preparation; Excavating and removing impacted soil; Removing septic tank contents; Closing septic tanks by filling them with clean soil; Collecting verification samples to verify that COCs have been removed to approved levels; Backfilling the excavations to surface grade with clean soil; Disposal of excavated materials following applicable federal, state, and DOE/NV regulations in accordance with Section 2.3 of the CAP (DOE/NV, 2000); and Decontamination of equipment as necessary. Closure was accomplished following the approved CAP (DOE/NV, 2000). Verification sample data demonstrate that all COCs were removed to the remediation standards. Therefore, the site is clean-closed.

Description:
The Area 25 Underground Storage Tanks site Corrective Action Unit (CAU) 135 will be closed by unrestricted release decontamination and verification survey, in accordance with the Federal Facility Agreement and Consert Order (FFACO, 1996). The CAU includes one Corrective Action Site (CAS). The Area 25 Underground Storage Tanks, (CAS 25-02-01), referred to as the Engine-Maintenance Assembly and Disassembly (E-MAD) Waste Holdup Tanks and Vault, were used to receive liquid waste from all of the radioactive drains at the E-MAD Facility. Based on the results of the Corrective Action Investigation conducted in June 1999 discussed in the Corrective Action Investigation Plan for Corrective Action Unit 135: Area 25 Underground Storage Tanks, Nevada Test Site, Nevada (DOE/NV,1999a), one sample from the radiological survey of the concrete vault interior exceeded radionuclide preliminary action levels. The analytes from the sediment samples that exceeded the preliminary action levels are polychlorinated biphenyls, Resource Conservation and Recovery Act metals, total petroleum hydrocarbons as diesel-range organics, and radionuclides. Unrestricted release decontamination and verification involves removal of concrete and the cement-lined pump sump from the vault. After verification that the contamination has been removed, the vault will be repaired with concrete, as necessary. The radiological- and chemical-contaminated pump sump and concrete removed from the vault would be disposed of at the Area 5 Radioactive Waste Management Site. The vault interior will be field surveyed following removal of contaminated material to verify that unrestricted release criteria have been achieved.

Description:
The Double Tracks Radiological Safety Area (DTRSA), Corrective Action Unit (CAU) 486, was clean-closed following the approved Corrective Action Decision Document closure alternative and in accordance with the Federal Facility Agreement and Consent Order. The CAU consists of a single Corrective Action Site, 71-23-001-71DT. The DTRSA was used during May 1963 to decontaminate vehicles, equipment, personnel and animals from the Double Tracks Test. Double Tracks was one of four storage-transportation tests. The Double Tracks test was conducted in Stonewall Flat, approximately 32 kilometers (20 miles) east of Goldfield, Nevada, on the Nellis Air Force Range. The Double Tracks Test used a single device containing plutonium and depleted uranium and was designed to investigate the characteristics of plutonium-bearing particulate material formed by the non-nuclear detonation of a nuclear weapon. All facilities associated with the DTRSA operation were removed. Based on available information, the areas of concern at the DTRSA consisted of a decon facility (vehicle decon pad and decon sump) in the southern half of the DTRSA, and a burial pit and former loading/unloading area located in the northern half of the DTRSA. Based on the results of the Corrective Action Investigation, radiological field screening detected elevated gamma and alpha readings on excavated plastic debris. Swipe surveys taken on the plastic debris detected removable alpha. No contaminants were detected above preliminary action levels in soil samples. The debris excavated during the corrective action investigation was not characterized. The clean-closure corrective action consisted of excavation, disposal, verification sampling, backfilling, and regrading. Field activities began on May 1, 2000, and ended on May 10, 2000. Soil that was associated with the radiologically contaminated man-made debris was placed into B-25 bins, moved to the designated waste management area where it was scanned, and hauled off-site for disposal. Verification soil samples were collected and analyzed ...

Description:
Corrective Action Unit (CAU) 135, Area 25 Underground Storage Tanks, was closed in accordance with the approved Corrective Action Plan (DOE/NV, 2000). CAU 135 consists of three Corrective Action Sites (CAS). Two of these CAS's were identified in the Corrective Action Investigation Data Quality Objective meeting as being improperly identified as underground storage tanks. CAS 25-02-03 identified as the Deluge Valve Pit was actually an underground electrical vault and CAS 25-02-10 identified as an Underground Storage Tank was actually a former above ground storage tank filled with demineralized water. Both of these CAS's are recommended for a no further action closure. CAS 25-02-01 the Underground Storage Tanks commonly referred to as the Engine Maintenance Assembly and Disassembly Waste Holdup Tanks and Vault was closed by decontaminating the vault structure and conducting a radiological verification survey to document compliance with the Nevada Test Site unrestricted use release criteria. The Area 25 Underground Storage Tanks, (CAS 25-02-01), referred to as the Engine Maintenance, Assembly, and Disassembly (E-MAD) Waste Holdup Tanks and Vault, were used to receive liquid waste from all of the radioactive and cell service area drains at the E-MAD Facility. Based on the results of the Corrective Action Investigation conducted in June 1999, discussed in ''The Corrective Action Investigation Plan for Corrective Action Unit 135: Area 25 Underground Storage Tanks, Nevada Test Site, Nevada'' (DOE/NV, 199a), one sample from the radiological survey of the concrete vault interior exceeded radionuclide preliminary action levels. The analytes from the sediment samples exceeded the preliminary action levels for polychlorinated biphenyls, Resource Conservation and Recovery Act metals, total petroleum hydrocarbons as diesel-range organics, and radionuclides. The CAU 135 closure activities consisted of scabbling radiological ''hot spots'' from the concrete vault, and the drilling removal of the cement-lined vault sump. Field activities began on November 28, ...